A network planning process involves several competing targets. The network should be compact and flexible to operate, and easy to expand. The network capacity and investments are planned to follow the expected transmission needs and the actual sales of transport services. There exist many alternative architectures to realize the network.
The first network investment of the operator must be reasonable in size, but big enough to ensure credibility and the near future growth of the network. In other words, a certain minimum coverage of the network is needed, and the growth of the network must be secured technically and economically at the same time.
Usually, these matters mean the need of building the network gradually, to add and modify network nodes and transmission lines. The changes in the network nodes can be frequent, which means repetitive additions of equipment, changes in the use of existing equipment, the increase of capacity, and adding more line interfaces. Usually, the changes also mean changes in synchronization paths and in network management channels.
Problems arise when the required changes are not possible to do in the existing nodes, or they can be done, but the existing resources are not used efficiently. For example, more capacity is needed in a node and thus new equipment must be added into the node, but there is no free space inside the rack. Or the added transmission capacity is for low capacity access traffic, but the node is capable of handling high capacity regional traffic, when the node is too big and expensive to handle just access traffic. In other words, the changes and the existing equipment must match with each other. Frequent changes in the future should be taken into account. The traffic in the network can be high or low capacity traffic, and dynamic or stable traffic in relation to the time period. The objective of the invention is to alleviate the above-mentioned drawbacks. This is achieved in a way described in the claims.